The invention relates to a hydraulically operated double clutch for a motor vehicle for the alternate coupling of a central shaft and of a hollow shaft which is concentric to this central shaft, of a speed change gear of a motor vehicle with the clutch housing driven by the engine output shaft the clutch includes at least one left clutch disk connected with the central shaft from one side and at least one right clutch disk connected with the central shaft from the other side, said at least one left and one right clutch disks being pressable against a center plate of the rotating clutch housing by means of annular pistons, these annular pistons being arranged concentrically with respect to the central shaft and being fitted in between a cover plate and a lateral plate of the clutch housing, which is screwed together with the cover plate.
This type of a double clutch is known from German Published Unexamined Application (DE-OS) 35 26 630. Two annular pistons, which are concentric with respect to one another and with respect to a central shaft, are fitted into a hydraulic plate composed of a cover plate and a base plate of the clutch housing which is screwed together with it. The annular pistons are penetrated by rods by means of which the two clutch disks are operated via pressure plates The rods of one annular piston are constructed as tension rods and, when acted upon by pressure, pull one clutch disk from one side against a center plate of the clutch housing The other clutch disk is pressed directly by means of the rods from the other side against the center plate. On the one side, the rods penetrate the annular pistons in the base plate and, on the other side, in the cover plate in a longitudinally movable and sealed off manner. For this purpose, the guide bores in the cover plate and in the base plate must be made very precisely and with narrow tolerances. The rods themselves represent turned parts which are machined at high cost.
It is an object of the invention to further develop a double clutch of this type in such a manner that less precise manufacturing tolerances will suffice and the double clutch can be manufactured at lower cost.
This object is achieved by constructing such a double clutch wherein one annular piston is fitted in at the junction plane between a left cover Plate and lateral plate, and the other annular piston being fitted in at a junction plane between a right cover plate and lateral plate of the clutch housing, and wherein the clutch disks with the annular pistons can be operated by means of several cylindrical pins which rest against their end faces and are guided in the lateral plates.
If, in accordance with certain preferred embodiments, instead of the rods, cylindrical pins are used which can be manufactured as mass-produced parts by means of continuous grinding, considerable costs are saved. Since the cylindrical pins are guided only in lateral plates of the clutch housing, these guide bores make only low demands on the tolerances, so that the manufacturing costs of the clutch are reduced further. The annular pistons and the flat cylindrical pins, which rest against them at the front face, may be arranged coaxially with respect to one another at both sides of the center plate or of the clutch disks to be pressed against it, and may be constructed as identical parts. The whole arrangement therefore becomes symmetrical with respect to the center plate and, when both clutches are operated, the same force-introducing conditions exist for both. Bundles of inner disks and outer disks which can be frictionally connected with the inner disks are preferably used as clutch disks. The disk bundles move in hydraulic fluid and form a wet clutch. Thus, possible sealing difficulties, which may occur in the case of a dry clutch, are eliminated
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.